The question of witness credibility is often the central issue of most cases that get to trial. Surprisingly it is a matter that barely features in legal education. A knowledge of the factors that a judge will take into account when assessing evidence should be a central part of the litigator’s toolbox.  The problem is compounded because, no matter how good an advocate you instruct, that advocate cannot make a witness credible.  This is particularly the case in civil proceedings where the witness statement stands as the evidence in chief. Advocacy on credibility, for the most part, consists of attacking the witnesses for the other side, whilst hoping that your own witnesses come out of cross-examination intact.


Some may argue that it is not the lawyer’s job to pre-determine this type of issue, in particular whether the client is telling the truth or not.  However in conditional fee cases the lawyer has to make an assessment of the overall credibility of the case. In privately funded litigation the client is entitled to an honest assessment of their prospects of success. This will involve consideration of how credible their case, and their witnesses are.  The dangerous thing is to rely on “gut instinct” or an assumption that “the client/witness seems honest”.  The process of evaluation of the evidence requires a more rigorous approach and one based on an understanding of the principles that are going to be applied when that evidence is considered.


There are several elements here.

  • The first is actually taking on a case and being able to scrutinise your own client’s credibility. If you are working on a conditional fee basis this is central to commercial survival.
  • Many cases which are subject to delays arise from problems with the client’s credibility.
  • Sometimes it is because a lawyer starts to appreciate that there are problems with the case that causes it to become a “fish file”. These are the files that are often subject to problems.
  • You should assume that every case will go to trial.  It is an important skill to be able, as best you can, to assess the credibility of your own and other witnesses.


This is a common misconception.  A witness can be totally honest and still totally wrong. Their are always different views of what happened and what was said. (Try asking competing football supporters whether a particular tackle should have been a penalty or not – they all saw the same thing, they have totally different views of what went on).  Further the memory distorts matters over time.

A common finding in a civil case is that a witness is totally honest but mistaken.  What has to be considered is whether the evidence will be found to be credible, not honest.  This means considering the view that a trial judge will take of that witness.


The courts in Northern Ireland have identified a number of factors, helpfully summarised by Stephens J in McAllister -v- Campbell [2014] NIQB 24

“[3] Before turning to the facts of the case I remind myself of what Mr Justice Gillen said in the case of Sean Thornton v Northern Ireland Housing Executive [2010] NIQB 4 in relation to the issue of credibility. At page 3 he said:
“[12] Credibility of a witness embraces not only the concept of his truthfulness i.e. whether the evidence of the witness is to be believed but also the objective reliability of the witness i.e. his ability to observe or remember facts and events about which the witness is giving evidence.
[13] In assessing credibility the court must pay attention to a number of factors which, inter alia, include the following;
The inherent probability or improbability of representations of fact ,
  • The presence of independent evidence tending to corroborate or undermine any given statement of fact,
  • The presence of contemporaneous records,
  • The demeanour of witnesses e.g. does he equivocate in cross examination,
  • The frailty of the population at large in accurately recollecting and describing events in the distant past,
  • Does the witness take refuge in wild speculation or uncorroborated allegations of fabrication,
  • Does the witness have a motive for misleading the court,
  • Weigh up one witness against another. “


A summary of the relevant principles to be considered when assessing the credibility of witnesses can be found in the judgments of HH Simon Brown Q.C.  in several cases but most markedly in Piper -v- Hales [2013] EWHC B1 (QB)

  1. The guidance about how courts approach this is given in the extra-judicial writing of the late Lord Bingham of Cornhill approved by the courts is apposite. In “The Judge as Juror: The Judicial Determination of Factual Issues” published in “The Business of Judging”, Oxford 2000, reprinted from Current Legal Problems, vol 38, 1985 p 1-27, he wrote:
“. . . Faced with a conflict of evidence on an issue substantially effecting the outcome of an action, often knowing that a decision this way or that will have momentous consequences on the parties’ lives or fortunes, how can and should the judge set about his task of resolving it ? How is he to resolve which witness is honest and which dishonest, which reliable and which unreliable? . . .
The normal first step in resolving issues of primary fact is, I feel sure, to add to what is common ground between the parties (which the pleadings in the action should have identified, but often do not) such facts as are shown to be incontrovertible. In many cases, letters or minutes written well before there was any breath of dispute between the parties may throw a very clear light on their knowledge and intentions at a particular time. In other cases, evidence of tyre marks, debris or where vehicles ended up may be crucial. To attach importance to matters such as these, which are independent of human recollection, is so obvious and standard a practice, and in some cases so inevitable, that no prolonged discussion is called for. It is nonetheless worth bearing in mind, when vexatious conflicts of oral testimony arise, that these fall to be judged against the background not only of what the parties agree to have happened but also of what plainly did happen, even though the parties do not agree.
The most compendious statement known to me of the judicial process involved in assessing the credibility of an oral witness is to be found in the dissenting speech of Lord Pearce in the House of Lords in Onassis v Vergottis [1968] 2 Lloyds Rep 403 at p 431. In this he touches on so many of the matters which I wish to mention that I may perhaps be forgiven for citing the relevant passage in full:
”Credibility’ involves wider problems than mere ‘demeanour’ which is mostly concerned with whether the witness appears to be telling the truth as he now believes it to be. Credibility covers the following problems. First, is the witness a truthful or untruthful person? Secondly, is he, though a truthful person telling something less than the truth on this issue, or though an untruthful person, telling the truth on this issue? Thirdly, though he is a truthful person telling the truth as he sees it, did he register the intentions of the conversation correctly and, if so has his memory correctly retained them? Also, has his recollection been subsequently altered by unconscious bias or wishful thinking or by over much discussion of it with others? Witnesses, especially those who are emotional, who think that they are morally in the right, tend very easily and unconsciously to conjure up a legal right that did not exist. It is a truism, often used in accident cases, that with every day that passes the memory becomes fainter and the imagination becomes more active. For that reason a witness, however honest, rarely persuades a Judge that his present recollection is preferable to that which was taken down in writing immediately after the accident occurred. Therefore, contemporary documents are always of the utmost importance. And lastly, although the honest witness believes he heard or saw this or that, is it so improbable that it is on balance more likely that he was mistaken? On this point it is essential that the balance of probability is put correctly into the scales in weighing the credibility of a witness. And motive is one aspect of probability. All these problems compendiously are entailed when a Judge assesses the credibility of a witness; they are all part of one judicial process. And in the process contemporary documents and admitted or incontrovertible facts and probabilities must play their proper part.”
Every judge is familiar with cases in which the conflict between the accounts of different witnesses is so gross as to be inexplicable save on the basis that one or some of the witnesses are deliberately giving evidence which they know to be untrue . . . . more often dishonest evidence is likely to be prompted by the hope of gain, the desire to avert blame or criticism, or misplaced loyalty to one or other of the parties. The main tests needed to determine whether a witness is lying or not are, I think, the following, although their relative importance will vary widely from case to case:

(1) the consistency of the witness’s evidence with what is agreed, or clearly shown by other evidence, to have occurred;

(2) the internal consistency of the witness’s evidence;

(3) consistency with what the witness has said or deposed on other occasions;

(4) the credit of the witness in relation to matters not germane to the litigation;

(5) the demeanour of the witness.

The first three of these tests may in general be regarded as giving a useful pointer to where the truth lies. If a witness’s evidence conflicts with what is clearly shown to have occurred, or is internally self-contradictory, or conflicts with what the witness has previously said, it may usually be regarded as suspect. It may only be unreliable, and not dishonest, but the nature of the case may effectively rule out that possibility.

The fourth test is perhaps more arguable. . . .”

The following guidance of Lord Goff in Grace Shipping v. Sharp & Co [1987] 1 Lloyd’s Law Rep. 207 at 215-6 is also helpful:.

“And it is not to be forgotten that, in the present case, the Judge was faced with the task of assessing the evidence of witnesses about telephone conversations which had taken place over five years before. In such a case, memories may very well be unreliable; and it is of crucial importance for the Judge to have regard to the contemporary documents and to the overall probabilities. In this connection, their Lordships wish to endorse a passage from a judgment of one of their number in Armagas Ltd v. Mundogas S.A. (The Ocean Frost), [1985] 1 Lloyd’s Rep. 1, when he said at p. 57:-


“Speaking from my own experience, I have found it essential in cases of fraud, when considering the credibility of witnesses, always to test their veracity by reference to the objective facts proved independently of their testimony, in particular by reference to the documents in the case, and also to pay particular regard to their motives and to the overall probabilities. It is frequently very difficult to tell whether a witness is telling the truth or not; and where there is a conflict of evidence such as there was in the present case, reference to the objective facts and documents, to the witnesses’ motives, and to the overall probabilities, can be of very great assistance to a Judge in ascertaining the truth.” [emphases added].

That observation is, in their Lordships’ opinion, equally apposite in a case where the evidence of the witnesses is likely to be unreliable; and it is to be remembered that in commercial cases, such as the present, there is usually a substantial body of contemporary documentary evidence.”

In that context he was impressed by a witness described in the following terms.

“Although like the other main witnesses his evidence was a mixture of reconstruction and original recollection, he took considerable trouble to distinguish precisely between the two, to an extent which I found convincing and reliable.”

That is so important, and so infrequently done.


  1. This approach to fact finding was amplified recently by Lady Justice Arden in the Court of Appeal in Wetton (as Liquidator of Mumtaz Properties) v. Ahmed and others [2011] EWCA Civ. 610, in paragraphs 11, 12 & 14:
11. By the end of the judgment, it is clear that what has impressed the judge most in his task of fact-finding was the absence, rather than the presence, of contemporary documentation or other independent oral evidence to confirm the oral evidence of the respondents to the proceedings.
12. There are many situations in which the court is asked to assess the credibility of witnesses from their oral evidence, that is to say, to weigh up their evidence to see whether it is reliable. Witness choice is an essential part of the function of a trial judge and he or she has to decide whose evidence, and how much evidence, to accept. This task is not to be carried out merely by reference to the impression that a witness made giving evidence in the witness box. It is not solely a matter of body language or the tone of voice or other factors that might generally be called the ‘demeanour’ of a witness. The judge should consider what other independent evidence would be available to support the witness. Such evidence would generally be documentary but it could be other oral evidence, for example, if the issue was whether a defendant was an employee, the judge would naturally consider whether there were any PAYE records or evidence, such as evidence in texts or e-mails, in which the defendant seeks or is given instructions as to how he should carry out work. This may be particularly important in cases where the witness is from a culture or way of life with which the judge may not be familiar. These situations can present particular dangers and difficulties to a judge.
14. In my judgment, contemporaneous written documentation is of the very greatest importance in assessing credibility. Moreover, it can be significant not only where it is present and the oral evidence can then be checked against it. It can also be significant if written documentation is absent. For instance, if the judge is satisfied that certain contemporaneous documentation is likely to have existed were the oral evidence correct, and that the party adducing oral evidence is responsible for its non-production, then the documentation may be conspicuous by its absence and the judge may be able to draw inferences from its absence.
Contemporaneity, consistency, probability and motive are key criteria and more important than demeanour which can be distorted through the prism of prejudice: how witnesses present themselves in a cramped witness box surrounded for the first time with multiple files can be distorted, particularly elderly ones being asked to remember minute details of what happened and what was said, and unrecorded, nearly 4 years later as here. Lengthy witness statements prepared by the parties’ lawyers long after the events also distort the accurate picture even though they are meant to assist the court.” (I have added the emphasis).


I have a lengthy post on the observations of Smith J in the Farepak case.  Here key observations are made about the preparation of witness statements and witness credibility. It was a statement made after an action to disqualify directions had to be withdrawn because the witness evidence in the witness box was vastly different to that in the witness statements.  The action got to the stage where witnesses were withdrawing parts of their statement before they were asked about them.

If I am reluctant to highlight aspects of the statement, but look in particular at:-

(1)          The advice at paragraph 47.

“47. The courts have regularly reminded parties that the purpose of witness statements is to replace oral testimony. It is not to rehearse arguments, it is not to set out a case and whilst it necessarily has to be drafted with the collaboration of lawyers, it should not be a document created in the language of lawyers by the lawyers, because the lawyers do not go into the witness box and defend it. This is unfair to defendants, as this case showed. It is also unfair to the witnesses. “

(2)          On contemporaneous documentation at paragraph 71:

“… we all know in litigation that the first port of call in any case is the contemporaneous documents: see what people said when they were not writing for posterity, i.e. a trial, and see whether what they say now can  be consistent with what they said then, and if it is inconsistent then find out why they say something different now to what they said at the time. This is an essential part of preparing evidence and Mr Kelly and the other witnesses were clearly unprepared for the ordeal –and it is an ordeal. Nobody knows what an ordeal giving evidence is in cases like this until they go into  the witness box and endure it. It is a hard, unyielding process and can be oppressive and unfair. We try and guard against that but at the end of the day the defendants have to put their case to the people who are put up for witnesses. It is not their fault if the witness evidence is not sustainable when matched with the contemporaneous documents. “

(3)          On the preparation of witness statements:

 “75. It might lengthen cases as regards preparation, but for every hour spent on preparation it has huge saving times in the trial and, of course, if positive first-hand evidence is provided the defendants will know what they have to meet and it might well lead them to conclude that they cannot contest it and it might well lead to more consensual resolution of these cases. However it is important that cases have to be prepared not on the basis that it is assumed they will capitulate but on the basis that they might fight, and if they are going to be prepared on that basis they must be properly prepared: (a) so that the accumulation of documents is not oppressive, (b) so that the witnesses are given a fair opportunity to present their evidence properly according to the contemporaneous documents; and(c) the defendants are given a fair opportunity to contest the allegations made against them by witnesses.”


All of these passages emphasise the importance the courts place on contemporaneous documents.


Whilst I am advocating looking at your own evidence with considerable care it should go without saying that your opponent’s evidence requires scrutinising on the same basis.  A failure to properly analyse the evidence could, in fact, be negligent.


The nature of the duty to examine witness evidence was considered by the Court of Appeal in Griffin –v- Kingsmill [2001] EWCA Civ. The Court allowed an appeal against a first instance finding that solicitors and counsel were not negligent in advising that a claim should be settled for £50,000.  The Court scrutinised the defendant’s witness evidence with care. The central issue in the case was whether the solicitor and counsel had properly evaluated the evidence presented by the defendant in the original claim.  Sir Murray Stuart Smith stated (at 64):-

This was essentially a simple case, though one of great importance for the claimant and her family. It was a case where the advice could be given after careful consideration. It was a case which was typical of many personal injury cases. Where if the claimant’s evidence, or that on his or her behalf is accepted, the claim will succeed. If the defendants’ account is accepted the claim will either fail or there will be a substantial contributory negligence. Where there is such a conflict it is very difficult, if not impossible at an earlier stage of the case, as this was, to be sure which evidence will be preferred. All that can be done is to point out what I have just said and then make some attempt to evaluate the strengths and weaknesses of the conflicting accounts”

 He went on, at 65,  to consider the care needed in evaluating conflicting evidence.

“On the face of it it is surprising result that advice which turns out to be one hundred per cent wrong in such a case was not negligent. The interested layman, or our old friend the officious bystander, might well ask “if the lawyers can be so wrong and they are considered to have acted in a way that competent and experienced lawyers could be expected to advise – why do we need lawyers?” I confess that I have listened with increasing amazement and some dismay to the submissions of counsel for the defence that the advice given here complied with the proper standard of care and competence. If that is so the profession should be ashamed that its standards are so low. I do not accept for one moment that this was the sort of advice that competent and experienced solicitors and counsel should have given. The judge thought that it was honestly and carefully given. There has never been any question about the honesty, but I am not at all clear how the judge arrived at the view that it was carefully given if he had correctly applied the law. It is not enough that counsel and solicitors have read the papers and given clear advice which could be understood. In a case such as this logical and sensible reasons have to be given for rejecting the favourable evidence of Mr Bailey. If the reasons do not bear examination they are not such as can be expected from a competent and experienced practitioner.”


Of particular importance was the Court’s statement of the need to consider the reliability of the original defendant (Mrs Grant).

“73.        Mr Purchas also submitted that the reliability of Mrs Grant’s account was not properly assessed. So far from being overwhelmingly likely that it would be accepted, there were very good grounds for thinking it would not be. Her oral statement to the police was inconsistent, as the judge said, with her written account of Victoria running along the pavement and across the verge into the road. Moreover, the third statement shows that the recollection was wholly vague and unreliable. These statements would have been a gift to any competent cross‑examiner. To my mind they were typical of a driver who is not keeping a proper lookout or paying attention and is suddenly confronted with a situation which she has failed to appreciate.”


 What was needed, therefore, was  a close and careful evaluation of the Defendant’s evidence.


There are many posts on this blog considering the principles in Gestmin.

To make life simple here is a bullet point version of the Gestmin principles.


  • There  obvious difficulty with allegations and oral evidence based on recollection of events which occurred several years ago is human memory.


  • Everyone knows human memory is fallible.
  • The legal system has not sufficiently absorbed the research into the nature of memory and the unreliability of eyewitness testimony.
  • We are not aware of the extent to which our own memories are unreliable and believe our memories to be more faithful than they are.


Two common and related errors are that:

  • The stronger and more vivid is our feeling or experience of recollection the more likely the recollection is to be accurate.
  • The more confident another person is in their recollection, the more likely their recollection is to be accurate.


Underlying both these errors is a faulty model of memory as a mental record which is fixed at the time of the event and fades over time.

  • Memories are fluid and malleable.
  • They are constantly rewritten whenever they are retrieved.
  • This is true of “flashbulb” memories of a shocking or traumatic event.
  • The very description “flashbulb” memories is misleading because it reflects the misconception that memory is like a camera.
  • External information can intrude into a witness’s memory as can their own thoughts and beliefs.
  • This can cause dramatic changes in recollection.
  • Events can be recalled as memories which did not happen at all or which happened to someone else (“a failure of a source of memory”.


Memory is unreliable when it comes to past beliefs.

  • Memories are revised to make them more consistent with our present beliefs.
  • Studies show that memory is particularly vulnerable to inference and alteration when a person is presented with new information or suggestions when their memory is already weak due to passage of time.


The process of civil litigation itself subjects the memories of witnesses to powerful biases.

  • Witnesses have a stake in a particular version of events.
  • This is more obvious in relation to parties and those with ties of loyalty to parties.
  • More subtle influences include the very process of making a witness statement and going to court to give evidence.
  • A desire to assist the party calling a witness and a natural desire to make a good impression can be significant motivating factors.


Considerable interference with memory is introduced by the process of preparing for trial.

  • A witness is often asked to make a statement a long time after the relevant events.
  • The statement is usually drafted by a lawyer who is lawyer who is conscious of the significance of the issues in the case.
  • The statement is made after a witness’s memory has been “refreshed” by reading documents.
  • The documents include pleadings and other argumentative material which the witness did not see at the time or which came into existence after the event.
  • The statement goes through several versions before it is finalised.
  • Months later the witness is asked to re-read the statement and documents before giving evidence in court.
  • The effect of this is to establish in the mind of the witness the matters in the statement and documents whether they be true or false.
  • This also causes the witness’s memory to be based increasingly on the material and later interpretations rather than the original events.


Witnesses are often asked in cross-examination the difference between reconstruction and recollection.

  • These questions are misguided.
  • There is a presumption that there is a clear distinction between recollection and reconstruction.
  • All remembering of distant events involves reconstruction processes.
  • Such questions disregard the fact that such processes are largely unconscious and that the strength, vividness and apparent authenticity of memories is not a reliable measure of their truth.


Mr Justice Legatt was particularly concerned with commercial cases. However, again, these matters are probably universal.

  • A judge places little, if any, reliance on witnesses’ recollections of what was said in meeting and conversations.
  • Factual findings are based on inferences drawn from the documentary evidence and known probable facts.


  •  Is the statement consistent with other statements prepared by the witness, with documents and with other witnesses.
  •  Consistency is a key issue. As the Griffin case shows inconsistent statements are “a gift to any competent cross examiner”
  • When drafting the statement consider issues of consistency.
  • Length is not always beneficial, particularly if is only reciting documents.
  • Always examine a statement against other statements and contemporary documents. This makes the most effective means of cross-examination.


  • The utility of witness evidence is often disproportionate to its length.
  • Its value largely lies in the opportunity which cross-examination affords to subject the documentary record to critical scrutiny and to gauge the personality, motivations and working practices of a witness rather than what the witness recalls of particulars conversations and events.


  • “Above all, it is important to avoid the fallacy of supposing that, because a witness has confidence in his or her recollection and is honest, evidence based on that recollection provides any reliable guide to the truth.”